The agarose gel electrophoretic system for the determination of lipoproteins has been improved and applied in the study of serum samples from normal subjects and patients with dyslipidemias. Abnormal lipoprotein patterns characterized by the absence of lipoprotein fractions and by the presence of extra fractions have been demonstrated and associated with defined pathological conditions. All these patterns form a reference record for the diagnosis and evaluation of lipoprotein abnormalities in normal subjects and patients. In addition an abnormal lipoprotein has been demonstrated in the serum of uremic patients which may be associated with accelerated atherosclerosis.